FM / algorithms

/usr/include/boost/geometry/algorithms

Name	Size	Mode	Actions
detail/	-	0755	rm
dispatch/	-	0755	rm
append.hpp	11493	0644	edit dl rm
area.hpp	10657	0644	edit dl rm
assign.hpp	10709	0644	edit dl rm
buffer.hpp	8656	0644	edit dl rm
centroid.hpp	19620	0644	edit dl rm
clear.hpp	5156	0644	edit dl rm
comparable_distance.hpp	1107	0644	edit dl rm
convert.hpp	17327	0644	edit dl rm
convex_hull.hpp	11589	0644	edit dl rm
correct.hpp	9956	0644	edit dl rm
correct_closure.hpp	5862	0644	edit dl rm
covered_by.hpp	1077	0644	edit dl rm
crosses.hpp	8478	0644	edit dl rm
densify.hpp	12472	0644	edit dl rm
difference.hpp	16591	0644	edit dl rm
discrete_frechet_distance.hpp	7844	0644	edit dl rm
discrete_hausdorff_distance.hpp	11281	0644	edit dl rm
disjoint.hpp	1191	0644	edit dl rm
distance.hpp	1110	0644	edit dl rm
envelope.hpp	1021	0644	edit dl rm
equals.hpp	1196	0644	edit dl rm
expand.hpp	1073	0644	edit dl rm
for_each.hpp	9831	0644	edit dl rm
intersection.hpp	806	0644	edit dl rm
intersects.hpp	1145	0644	edit dl rm
is_convex.hpp	6508	0644	edit dl rm
is_empty.hpp	4853	0644	edit dl rm
is_simple.hpp	575	0644	edit dl rm
is_valid.hpp	570	0644	edit dl rm
length.hpp	9341	0644	edit dl rm
line_interpolate.hpp	13054	0644	edit dl rm
make.hpp	5170	0644	edit dl rm
not_implemented.hpp	3839	0644	edit dl rm
num_geometries.hpp	3586	0644	edit dl rm
num_interior_rings.hpp	3756	0644	edit dl rm
num_points.hpp	5565	0644	edit dl rm
num_segments.hpp	4775	0644	edit dl rm
overlaps.hpp	1067	0644	edit dl rm
perimeter.hpp	7212	0644	edit dl rm
point_on_surface.hpp	13281	0644	edit dl rm
relate.hpp	642	0644	edit dl rm
relation.hpp	652	0644	edit dl rm
remove_spikes.hpp	9753	0644	edit dl rm
reverse.hpp	4386	0644	edit dl rm
simplify.hpp	22696	0644	edit dl rm
sym_difference.hpp	23169	0644	edit dl rm
touches.hpp	1127	0644	edit dl rm
transform.hpp	14105	0644	edit dl rm
union.hpp	21383	0644	edit dl rm
unique.hpp	4682	0644	edit dl rm
validity_failure_type.hpp	3684	0644	edit dl rm
within.hpp	1057	0644	edit dl rm

Edit: /usr/include/boost/geometry/algorithms/centroid.hpp (19620B)

// Boost.Geometry (aka GGL, Generic Geometry Library)

// Copyright (c) 2007-2015 Barend Gehrels, Amsterdam, the Netherlands.
// Copyright (c) 2008-2015 Bruno Lalande, Paris, France.
// Copyright (c) 2009-2015 Mateusz Loskot, London, UK.
// Copyright (c) 2014-2017 Adam Wulkiewicz, Lodz, Poland.

// This file was modified by Oracle on 2014, 2015.
// Modifications copyright (c) 2014-2015 Oracle and/or its affiliates.

// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
// Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle

// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.

// Use, modification and distribution is subject to the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

#ifndef BOOST_GEOMETRY_ALGORITHMS_CENTROID_HPP
#define BOOST_GEOMETRY_ALGORITHMS_CENTROID_HPP

#include <cstddef>

#include <boost/core/ignore_unused.hpp>
#include <boost/range.hpp>
#include <boost/throw_exception.hpp>

#include <boost/variant/apply_visitor.hpp>
#include <boost/variant/static_visitor.hpp>
#include <boost/variant/variant_fwd.hpp>

#include <boost/geometry/core/closure.hpp>
#include <boost/geometry/core/cs.hpp>
#include <boost/geometry/core/coordinate_dimension.hpp>
#include <boost/geometry/core/exception.hpp>
#include <boost/geometry/core/exterior_ring.hpp>
#include <boost/geometry/core/interior_rings.hpp>
#include <boost/geometry/core/tag_cast.hpp>
#include <boost/geometry/core/tags.hpp>
#include <boost/geometry/core/point_type.hpp>

#include <boost/geometry/geometries/concepts/check.hpp>

#include <boost/geometry/algorithms/assign.hpp>
#include <boost/geometry/algorithms/convert.hpp>
#include <boost/geometry/algorithms/detail/interior_iterator.hpp>
#include <boost/geometry/algorithms/detail/point_on_border.hpp>
#include <boost/geometry/algorithms/not_implemented.hpp>
#include <boost/geometry/strategies/centroid.hpp>
#include <boost/geometry/strategies/concepts/centroid_concept.hpp>
#include <boost/geometry/strategies/default_strategy.hpp>
#include <boost/geometry/views/closeable_view.hpp>

#include <boost/geometry/util/for_each_coordinate.hpp>
#include <boost/geometry/util/select_coordinate_type.hpp>

#include <boost/geometry/algorithms/is_empty.hpp>

#include <boost/geometry/algorithms/detail/centroid/translating_transformer.hpp>

namespace boost { namespace geometry
{

#if ! defined(BOOST_GEOMETRY_CENTROID_NO_THROW)

/*!
\brief Centroid Exception
\ingroup centroid
\details The centroid_exception is thrown if the free centroid function is called with
    geometries for which the centroid cannot be calculated. For example: a linestring
    without points, a polygon without points, an empty multi-geometry.
\qbk{
[heading See also]
\* [link geometry.reference.algorithms.centroid the centroid function]
}

*/
class centroid_exception : public geometry::exception
{
public:

/*!
    \brief The default constructor
    */
    inline centroid_exception() {}

/*!
    \brief Returns the explanatory string.
    \return Pointer to a null-terminated string with explanatory information.
    */
    virtual char const* what() const throw()
    {
        return "Boost.Geometry Centroid calculation exception";
    }
};

#endif

#ifndef DOXYGEN_NO_DETAIL
namespace detail { namespace centroid
{

struct centroid_point
{
    template<typename Point, typename PointCentroid, typename Strategy>
    static inline void apply(Point const& point, PointCentroid& centroid,
            Strategy const&)
    {
        geometry::convert(point, centroid);
    }
};

template
<
    typename Indexed,
    typename Point,
    std::size_t Dimension = 0,
    std::size_t DimensionCount = dimension<Indexed>::type::value
>
struct centroid_indexed_calculator
{
    typedef typename select_coordinate_type
        <
            Indexed, Point
        >::type coordinate_type;
    static inline void apply(Indexed const& indexed, Point& centroid)
    {
        coordinate_type const c1 = get<min_corner, Dimension>(indexed);
        coordinate_type const c2 = get<max_corner, Dimension>(indexed);
        coordinate_type m = c1 + c2;
        coordinate_type const two = 2;
        m /= two;

set<Dimension>(centroid, m);

centroid_indexed_calculator
            <
                Indexed, Point, Dimension + 1
            >::apply(indexed, centroid);
    }
};

template<typename Indexed, typename Point, std::size_t DimensionCount>
struct centroid_indexed_calculator<Indexed, Point, DimensionCount, DimensionCount>
{
    static inline void apply(Indexed const& , Point& )
    {
    }
};

struct centroid_indexed
{
    template<typename Indexed, typename Point, typename Strategy>
    static inline void apply(Indexed const& indexed, Point& centroid,
            Strategy const&)
    {
        centroid_indexed_calculator
            <
                Indexed, Point
            >::apply(indexed, centroid);
    }
};

// There is one thing where centroid is different from e.g. within.
// If the ring has only one point, it might make sense that
// that point is the centroid.
template<typename Point, typename Range>
inline bool range_ok(Range const& range, Point& centroid)
{
    std::size_t const n = boost::size(range);
    if (n > 1)
    {
        return true;
    }
    else if (n <= 0)
    {
#if ! defined(BOOST_GEOMETRY_CENTROID_NO_THROW)
        BOOST_THROW_EXCEPTION(centroid_exception());
#else
        return false;
#endif
    }
    else // if (n == 1)
    {
        // Take over the first point in a "coordinate neutral way"
        geometry::convert(*boost::begin(range), centroid);
        return false;
    }
    //return true; // unreachable
}

/*!
    \brief Calculate the centroid of a Ring or a Linestring.
*/
template <closure_selector Closure>
struct centroid_range_state
{
    template<typename Ring, typename PointTransformer, typename Strategy>
    static inline void apply(Ring const& ring,
                             PointTransformer const& transformer,
                             Strategy const& strategy,
                             typename Strategy::state_type& state)
    {
        boost::ignore_unused(strategy);

typedef typename geometry::point_type<Ring const>::type point_type;
        typedef typename closeable_view<Ring const, Closure>::type view_type;

typedef typename boost::range_iterator<view_type const>::type iterator_type;

view_type view(ring);
        iterator_type it = boost::begin(view);
        iterator_type end = boost::end(view);

if (it != end)
        {
            typename PointTransformer::result_type
                previous_pt = transformer.apply(*it);

for ( ++it ; it != end ; ++it)
            {
                typename PointTransformer::result_type
                    pt = transformer.apply(*it);

strategy.apply(static_cast<point_type const&>(previous_pt),
                               static_cast<point_type const&>(pt),
                               state);

previous_pt = pt;
            }
        }
    }
};

template <closure_selector Closure>
struct centroid_range
{
    template<typename Range, typename Point, typename Strategy>
    static inline bool apply(Range const& range, Point& centroid,
                             Strategy const& strategy)
    {
        if (range_ok(range, centroid))
        {
            // prepare translation transformer
            translating_transformer<Range> transformer(*boost::begin(range));
            
            typename Strategy::state_type state;
            centroid_range_state<Closure>::apply(range, transformer,
                                                 strategy, state);
            
            if ( strategy.result(state, centroid) )
            {
                // translate the result back
                transformer.apply_reverse(centroid);
                return true;
            }
        }

return false;
    }
};

/*!
    \brief Centroid of a polygon.
    \note Because outer ring is clockwise, inners are counter clockwise,
    triangle approach is OK and works for polygons with rings.
*/
struct centroid_polygon_state
{
    template<typename Polygon, typename PointTransformer, typename Strategy>
    static inline void apply(Polygon const& poly,
                             PointTransformer const& transformer,
                             Strategy const& strategy,
                             typename Strategy::state_type& state)
    {
        typedef typename ring_type<Polygon>::type ring_type;
        typedef centroid_range_state<geometry::closure<ring_type>::value> per_ring;

per_ring::apply(exterior_ring(poly), transformer, strategy, state);

typename interior_return_type<Polygon const>::type
            rings = interior_rings(poly);

for (typename detail::interior_iterator<Polygon const>::type
                it = boost::begin(rings); it != boost::end(rings); ++it)
        {
            per_ring::apply(*it, transformer, strategy, state);
        }
    }
};

struct centroid_polygon
{
    template<typename Polygon, typename Point, typename Strategy>
    static inline bool apply(Polygon const& poly, Point& centroid,
                             Strategy const& strategy)
    {
        if (range_ok(exterior_ring(poly), centroid))
        {
            // prepare translation transformer
            translating_transformer<Polygon>
                transformer(*boost::begin(exterior_ring(poly)));
            
            typename Strategy::state_type state;
            centroid_polygon_state::apply(poly, transformer, strategy, state);
            
            if ( strategy.result(state, centroid) )
            {
                // translate the result back
                transformer.apply_reverse(centroid);
                return true;
            }
        }

return false;
    }
};

/*!
    \brief Building block of a multi-point, to be used as Policy in the
        more generec centroid_multi
*/
struct centroid_multi_point_state
{
    template <typename Point, typename PointTransformer, typename Strategy>
    static inline void apply(Point const& point,
                             PointTransformer const& transformer,
                             Strategy const& strategy,
                             typename Strategy::state_type& state)
    {
        boost::ignore_unused(strategy);
        strategy.apply(static_cast<Point const&>(transformer.apply(point)),
                       state);
    }
};

/*!
    \brief Generic implementation which calls a policy to calculate the
        centroid of the total of its single-geometries
    \details The Policy is, in general, the single-version, with state. So
        detail::centroid::centroid_polygon_state is used as a policy for this
        detail::centroid::centroid_multi

*/
template <typename Policy>
struct centroid_multi
{
    template <typename Multi, typename Point, typename Strategy>
    static inline bool apply(Multi const& multi,
                             Point& centroid,
                             Strategy const& strategy)
    {
#if ! defined(BOOST_GEOMETRY_CENTROID_NO_THROW)
        // If there is nothing in any of the ranges, it is not possible
        // to calculate the centroid
        if (geometry::is_empty(multi))
        {
            BOOST_THROW_EXCEPTION(centroid_exception());
        }
#endif

// prepare translation transformer
        translating_transformer<Multi> transformer(multi);

typename Strategy::state_type state;

for (typename boost::range_iterator<Multi const>::type
                it = boost::begin(multi);
            it != boost::end(multi);
            ++it)
        {
            Policy::apply(*it, transformer, strategy, state);
        }

if ( strategy.result(state, centroid) )
        {
            // translate the result back
            transformer.apply_reverse(centroid);
            return true;
        }
        
        return false;
    }
};

template <typename Algorithm>
struct centroid_linear_areal
{
    template <typename Geometry, typename Point, typename Strategy>
    static inline void apply(Geometry const& geom,
                             Point& centroid,
                             Strategy const& strategy)
    {
        if ( ! Algorithm::apply(geom, centroid, strategy) )
        {
            geometry::point_on_border(centroid, geom);
        }
    }
};

}} // namespace detail::centroid
#endif // DOXYGEN_NO_DETAIL

#ifndef DOXYGEN_NO_DISPATCH
namespace dispatch
{

template
<
    typename Geometry,
    typename Tag = typename tag<Geometry>::type
>
struct centroid: not_implemented<Tag>
{};

template <typename Geometry>
struct centroid<Geometry, point_tag>
    : detail::centroid::centroid_point
{};

template <typename Box>
struct centroid<Box, box_tag>
    : detail::centroid::centroid_indexed
{};

template <typename Segment>
struct centroid<Segment, segment_tag>
    : detail::centroid::centroid_indexed
{};

template <typename Ring>
struct centroid<Ring, ring_tag>
    : detail::centroid::centroid_linear_areal
        <
            detail::centroid::centroid_range<geometry::closure<Ring>::value>
        >
{};

template <typename Linestring>
struct centroid<Linestring, linestring_tag>
    : detail::centroid::centroid_linear_areal
        <
            detail::centroid::centroid_range<closed>
        >
{};

template <typename Polygon>
struct centroid<Polygon, polygon_tag>
    : detail::centroid::centroid_linear_areal
        <
            detail::centroid::centroid_polygon
        >
{};

template <typename MultiLinestring>
struct centroid<MultiLinestring, multi_linestring_tag>
    : detail::centroid::centroid_linear_areal
        <
            detail::centroid::centroid_multi
            <
                detail::centroid::centroid_range_state<closed>
            >
        >
{};

template <typename MultiPolygon>
struct centroid<MultiPolygon, multi_polygon_tag>
    : detail::centroid::centroid_linear_areal
        <
            detail::centroid::centroid_multi
            <
                detail::centroid::centroid_polygon_state
            >
        >
{};

template <typename MultiPoint>
struct centroid<MultiPoint, multi_point_tag>
    : detail::centroid::centroid_multi
        <
            detail::centroid::centroid_multi_point_state
        >
{};

} // namespace dispatch
#endif // DOXYGEN_NO_DISPATCH

namespace resolve_strategy {

template <typename Geometry>
struct centroid
{
    template <typename Point, typename Strategy>
    static inline void apply(Geometry const& geometry, Point& out, Strategy const& strategy)
    {
        dispatch::centroid<Geometry>::apply(geometry, out, strategy);
    }

template <typename Point>
    static inline void apply(Geometry const& geometry, Point& out, default_strategy)
    {
        typedef typename strategy::centroid::services::default_strategy
        <
            typename cs_tag<Geometry>::type,
            typename tag_cast
                <
                    typename tag<Geometry>::type,
                    pointlike_tag,
                    linear_tag,
                    areal_tag
                >::type,
            dimension<Geometry>::type::value,
            Point,
            Geometry
        >::type strategy_type;

dispatch::centroid<Geometry>::apply(geometry, out, strategy_type());
    }
};

} // namespace resolve_strategy

namespace resolve_variant {

template <typename Geometry>
struct centroid
{
    template <typename Point, typename Strategy>
    static inline void apply(Geometry const& geometry, Point& out, Strategy const& strategy)
    {
        concepts::check_concepts_and_equal_dimensions<Point, Geometry const>();
        resolve_strategy::centroid<Geometry>::apply(geometry, out, strategy);
    }
};

template <BOOST_VARIANT_ENUM_PARAMS(typename T)>
struct centroid<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> >
{
    template <typename Point, typename Strategy>
    struct visitor: boost::static_visitor<void>
    {
        Point& m_out;
        Strategy const& m_strategy;

visitor(Point& out, Strategy const& strategy)
        : m_out(out), m_strategy(strategy)
        {}

template <typename Geometry>
        void operator()(Geometry const& geometry) const
        {
            centroid<Geometry>::apply(geometry, m_out, m_strategy);
        }
    };

template <typename Point, typename Strategy>
    static inline void
    apply(boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> const& geometry,
          Point& out,
          Strategy const& strategy)
    {
        boost::apply_visitor(visitor<Point, Strategy>(out, strategy), geometry);
    }
};

} // namespace resolve_variant

/*!
\brief \brief_calc{centroid} \brief_strategy
\ingroup centroid
\details \details_calc{centroid,geometric center (or: center of mass)}. \details_strategy_reasons
\tparam Geometry \tparam_geometry
\tparam Point \tparam_point
\tparam Strategy \tparam_strategy{Centroid}
\param geometry \param_geometry
\param c \param_point \param_set{centroid}
\param strategy \param_strategy{centroid}

\qbk{distinguish,with strategy}
\qbk{[include reference/algorithms/centroid.qbk]}
\qbk{[include reference/algorithms/centroid_strategies.qbk]}
}

*/
template<typename Geometry, typename Point, typename Strategy>
inline void centroid(Geometry const& geometry, Point& c,
        Strategy const& strategy)
{
    resolve_variant::centroid<Geometry>::apply(geometry, c, strategy);
}

/*!
\brief \brief_calc{centroid}
\ingroup centroid
\details \details_calc{centroid,geometric center (or: center of mass)}. \details_default_strategy
\tparam Geometry \tparam_geometry
\tparam Point \tparam_point
\param geometry \param_geometry
\param c The calculated centroid will be assigned to this point reference

\qbk{[include reference/algorithms/centroid.qbk]}
\qbk{
[heading Example]
[centroid]
[centroid_output]
}
 */
template<typename Geometry, typename Point>
inline void centroid(Geometry const& geometry, Point& c)
{
    geometry::centroid(geometry, c, default_strategy());
}

/*!
\brief \brief_calc{centroid}
\ingroup centroid
\details \details_calc{centroid,geometric center (or: center of mass)}. \details_return{centroid}.
\tparam Point \tparam_point
\tparam Geometry \tparam_geometry
\param geometry \param_geometry
\return \return_calc{centroid}

\qbk{[include reference/algorithms/centroid.qbk]}
 */
template<typename Point, typename Geometry>
inline Point return_centroid(Geometry const& geometry)
{
    Point c;
    geometry::centroid(geometry, c);
    return c;
}

/*!
\brief \brief_calc{centroid} \brief_strategy
\ingroup centroid
\details \details_calc{centroid,geometric center (or: center of mass)}. \details_return{centroid}. \details_strategy_reasons
\tparam Point \tparam_point
\tparam Geometry \tparam_geometry
\tparam Strategy \tparam_strategy{centroid}
\param geometry \param_geometry
\param strategy \param_strategy{centroid}
\return \return_calc{centroid}

\qbk{distinguish,with strategy}
\qbk{[include reference/algorithms/centroid.qbk]}
\qbk{[include reference/algorithms/centroid_strategies.qbk]}
 */
template<typename Point, typename Geometry, typename Strategy>
inline Point return_centroid(Geometry const& geometry, Strategy const& strategy)
{
    Point c;
    geometry::centroid(geometry, c, strategy);
    return c;
}

}} // namespace boost::geometry

#endif // BOOST_GEOMETRY_ALGORITHMS_CENTROID_HPP

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